This specification relates to digital rights management.
Publishers, distributors, retailers and other providers of electronic content often desire to restrict access to the electronic content to authorized users only. Electronic content may include, for example, documents, e-books, video, music, computer applications, or games, to name a few examples. Electronic content may be usable on a variety of devices, such as a personal computer, laptop computer, tablet computer, television, set-top box, gaming system, and various types of mobile devices (e.g., personal digital assistant (PDA), portable music player, mobile phone). Electronic content may be distributed, for example, in some encrypted or otherwise protected form. Encrypted content may require a decryption key or other mechanism for rendering the document usable to an authorized user. Some types of user devices may include hardware that is specialized for certain encryption and decryption processing.
When electronic content is distributed, e.g., sold or lent to consumers, the electronic content can be protected by a digital rights management (“DRM”) system. A DRM system defines and enforces digital rights. A digital right is a permission to perform one or more actions that involve a content item. By managing digital rights, the DRM system can allow content owners to prevent unauthorized use or distribution of the protected content and can selectively authorize users to perform actions that involve the protected content. For example, upon request, the DRM system can evaluate a set of digital rights associated with a content item, and based on the evaluation, provide or deny authorization for an action involving the content item.